It is quite common in a number of situations for a person to be required to wear a gas mask or full face respirator. Firefighters, chemical workers, police officers in certain situations, hazardous material disposal personnel and the like are only a few examples of the wide range of people who must wear a full face respirator or gas mask during at least a portion of their working day. Such full face respirators or gas masks typically include a wraparound clear plastic lens that is supported in a soft, pliable silicone facepiece. While other styles of full face respirators and gas masks are available on the market, the typical configuration is as described above.
A substantial number of the people whose work environment requires the use of such a full face respirator or gas mask are also required to wear some type of corrective lenses because of visual limitations. In a normal situation, such as in a non-hazardous environment, many of these visually challenged workers would rely on contact lenses or on eyeglasses which are provided with generally well-known side pieces.
Many people however, cannot wear contact lenses for a variety of reasons. As a result, many users of full face respirators or gas masks often do not use contact lenses when they are wearing these full face masks. Instead, they rely on more conventional spectacles.
A full face mask will typically have its soft, pliable facepiece, fabricated of silicon or the like, define a seal around the wearer's eyes, nose and mouth. That seal typically depends on a positive contact between the soft, pliable material of the facepiece and the skin of the wearers. Facial hair, such as a beard, is apt to compromise the ability of the facepiece to form a positive, leakproof seal. For that reason, most full face masks do not cover the wearer's ears. To do so would require, on most wearers, that a seal be made against the wearer's scalp which is typically covered with hair.
As is well known, conventional eyeglasses include side pieces that extend from the lens frame of the eyeglasses, across the temples of the wearer and which attach about the wearer's ears. These side pieces would thus have to pass under the edge of the facepiece and would therefor compromise the seal integrity of the facepiece.
The assignee of the subject application, Mine Safety Appliances Company (“MSA”), of Pittsburgh, Pa., is a supplier of a large number of full face respirators and gas masks. They are also the assignee of U.S. Pat. No. 3,563,640, which is directed to a device for holding spectacles in a mask. That patented device has been commercialized in an MSA Spectacle Kit which has been widely sold and used. As may be seen in that patent, the device for holding spectacles is a mount including a spring wire with a central downwardly extending loop that supports a friction member. The friction member is configured to support a spectacle frame and the spring wire is adapted to be secured in a channel or groove that defines the juncture between the wraparound lens and the facepiece.
While this prior MSA device has enjoyed substantial commercial success, it has been determined that the prior spectacle holding device does not provide as much stability, in the mounting of the eyeglasses, as may be required for certain use applications. A number of wearers of full face masks engage in rather strenuous activities. Firefighters are a group of users of full face respirators or gas masks who, in the course of their occupational activities, engage in running, jumping and other similar activities where it is imperative that the spectacle holding and mounting device must be able to retain the spectacles in their intended position. Lenses for eyeglasses are ground based on a distance from the lens to the user's eye. If that distance varies by too great an amount, the user's vision is impaired. Eyeglass lenses are also ground or formed so that their optical centers will be aligned with the wearer's pupils. If the eyeglasses shift or are dislodged, so that the optimum alignment is compromised, the vision of the user will again be degraded.
It will thus be appreciated that there is a need for improved devices for holding eyeglasses or spectacles in a full face respirator or gas mask. The spectacle frame mount, in accordance with the present invention, overcomes the limitations of the known devices and is a substantial advance in the art.